Earth Data School
About
Full catalog/EN1_MDSI_MER_RR__1P
EN1_MDSI_MER_RR__1P·v4·dataset

Raw light measured at top of atmosphere (Envisat)

Reduced Resolution Geolocated and Calibrated TOA Radiance
atmosphere NASA LAADS Level 1B netCDF-4
In plain English

What it measures. Calibrated readings of how much light, across 15 color bands, reached the sensor at the top of the atmosphere, at reduced (coarser) resolution.

How it's made. Recorded by the MERIS imaging spectrometer on Europe's Envisat satellite, then geolocated and calibrated into proper units (an early-stage Level-1 product).

How & where you'd use it. A building-block input used to derive higher-level ocean and land products; most people use those finished products rather than these raw radiances.

What's measured

ATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › CLOUD PRECIPITABLE WATERLAND SURFACE › LANDSCAPE › LANDSCAPE ECOLOGYOCEANS › OCEAN OPTICS › OCEAN COLORSPECTRAL/ENGINEERING › VISIBLE WAVELENGTHS › VISIBLE RADIANCESPECTRAL/ENGINEERING › ULTRAVIOLET WAVELENGTHS › ULTRAVIOLET RADIANCESPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › INFRARED RADIANCEATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD CEILING

Coverage & cadence

  • Time span2002-04-29 → 2012-04-08
  • Measured byENVISAT (MERIS)
  • Processing levelLevel 1B
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusCOMPLETE

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

The Medium Resolution Imaging Spectrometer (MERIS) is one of 10 sensors deployed in March of 2002 on board the polar-orbiting Envisat-1 environmental research satellite by the European Space Agency (ESA). The MERIS instrument is a moderate-resolution wide field-of-view push-broom imaging spectroradiometer capable of sensing in the 390 nm to 1040 nm spectral range. Being a programmable instrument, it had the unique capability of selectively adjusting the width and location of its 15 bands through ground command. The instrument has a 68.5-degree field of view and a swath width of 1150 meters, providing a global coverage every 3 days at 300 m resolution. Communication with the Envisat-1 satellite was lost suddenly on the 8th of April, 2012, just weeks after celebrating its 10th year in orbit. All attempts to re-establish contact were unsuccessful, and the end of the mission was declared on May 9th, 2012. The 4th reprocessing cycle, in 2020, has produced both the full-resolution and reduced-resolution L1 and L2 MERIS products. EN1_MDSI_MER_RR__1P is the short-name for the MERIS Level-1 reduced resolution, geolocated and calibrated top-of-atmosphere (TOA) radiance product. This product contains the TOA upwelling spectral radiance measurements at reduced resolution. The in-band reference irradiances for the 15 MERIS bands are computed by averaging the in-band solar irradiance for each pixel. Each pixel’s in-band solar irradiance is computed by integrating the reference solar spectrum with the band-pass of each pixel. The Level-1 product contains 22 data files: 15 files contain radiances for each band (one band per file) along with associated error estimates, and 7 annotation data files. It also includes a Manifest file that provides metadata information describing the product.

Get the data

en1_mdsi_mer_rr__1p_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="EN1_MDSI_MER_RR__1P",
    version="4",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.